1. Field of the Invention
The present invention relates to a handle used on a hand held power tool that rotates a grinding wheel, buffing wheel, or sanding wheel. The invention relates particularly to a handle of an industrial grinder.
2. Description of Related Art
FIG. 1 shows a prior art power tool 1. In general, such a tool has a body that houses an electric motor and a drive train which terminates in a rotatable drive shaft. The rotatable drive shaft extends from the body and is usually adapted to engage attachments such as wheel 9. Typical attachments for power tool 1 include a grinding wheel, a saw blade, a buffing wheel, or a sanding wheel. The attachments are commonly interchangeable.
Power tool 1 or grinder 1, is sold commercially with a detachable protruding pole handle 3. Pole handle 3 has a bicycle-type grip. Pole handle 3 can be screwed into one of threaded holes 5 or 7 depending on the location in which grinder 1 is being used.
Commercially available grinders similar to grinder 1 with pole handle 3 are listed below:
______________________________________ Manufacturer Description Model No. ______________________________________ Black & Decker 7 in. Sander Polisher No. 9531 Black & Decker 41/2 in. Angle Grinder No. 2750 Black & Decker 7 in. Sander No. 4076 Black & Decker 7 in./9 in. Sander No. 4049 RYOBI 4 in. Grinder No. SG 1000 Milwaukee 41/2 in. Sander-Grinder No. 6145 ______________________________________
Other companies such as Mikita and Sears also offer grinders with pole handles similar to pole handle 3.
Unfortunately, pole handle 3 does not always provide complete safety and flexibility for the user. Pole handle 3 tends to slip out of the user's hand when the grinding wheel or other type rotating tool suddenly stops. This can happen when wheel 9 is pinched during cutting, grinding, or buffing to clean the end of a pipe. Operators in chemical plant construction typically remove handle 3 when working in close quarters which further decreases safety. Pole handles are also typically removed from grinders used on oil or gas pipelines because changing pole handle 3 between threaded holes 5 and 7 is required to grind around the circumference of a pipe, a time consuming task. Absence of a handle makes the grinder more difficult to control and much more likely to slip out of the operator's hand and cause injuries.
FIG. 2 shows a situation where no handle on grinder 1 is used because the handle would have to be constantly swapped from side to side when extending a cut, grind, or buff 13 around the circumference of a typical 36 in. diameter gas pipeline 15. Pole handle 3 may also be constantly removed and replaced because ground 17 is too close to the pipeline to grind beneath with the pole handle attached. As mentioned previously, when grinders are used without a handle as shown in FIG. 2, the grinder is more likely to slip out of the operator's hands and cause severe injuries.